Process and Product Innovation: Complementarity in a Vertically Differentiated Monopoly with Discrete Consumer Types

This paper examines the complementarity between process and product innovation where process innovation reduces the marginal cost of quality. In the context of a vertically differentiated monopolistic market with discrete consumer types, we investigate how the nature of (fixed versus variable) innovation costs and the distribution of consumers over different types affect the complementarity between process and product innovation. We show that under variable innovation costs a process innovation is more likely to occur alone than both innovations together when taste diversity (or consumer heterogeneity) is not significant and/or when there are more low‐type than high‐type consumers.